Find all decorated functions in a module

Question

Is it possible to find out if a function is decorated at runtime? For example could I find all functions in a module that are decorated by "example"?

@example
def test1():
    print "test1"

Answer 1

In the general case it is not possible because the example decorator might not leave any trace that's detectable at runtime -- for example, it could be

def example(f):
  return f

If you do control the source for example, it's of course easy to make it mark or record the functions it's decorating; if you don't, it may be utterly impossible to do what you want.

Answer 2

I don't think there's a general way since a decorator is a simple function call. Your code is identical to this:

def test1():
    print "test1"

test1 = example(test1)

You could probably detect specific decorators by disassembling and analysing (using the dis module). Or you could simply parse the source file, though that's a bit ugly.

Why do you want to detect them in the first place?

Answer 3

If you can, monkeypatch the decorator at runtime to catch which functions are being passed to it:

decfuncs = []

def decpatch(dec):
  def catchdec(func, *args, **kwargs):
    decfuncs.append(func)
    return dec(func, *args, **kwargs)
  return catchdec

somemodule.somedecorator = decpatch(somemodule.somedecorator)

Answer 4

Since you have indicated that you are have control of the wrapper code, here is a simple example

def example(f):
    f.wrapped=True
    return f

@example
def test1():
    print "test1"

def test2():
    print "test2"


print test1.wrapped
print hasattr(test2,'wrapped')